U.S. patent application number 12/412422 was filed with the patent office on 2009-12-10 for switch device for ratchet wrench.
Invention is credited to Bobby Hu.
Application Number | 20090301266 12/412422 |
Document ID | / |
Family ID | 41317954 |
Filed Date | 2009-12-10 |
United States Patent
Application |
20090301266 |
Kind Code |
A1 |
Hu; Bobby |
December 10, 2009 |
Switch Device for Ratchet Wrench
Abstract
A ratchet wrench includes a head (11) having a through-hole (13)
rotatably receiving a drive member (20). A pawl (30) is pivotably
received in a compartment (22) in the drive member (20). A switch
member (42) is rotatably mounted to an end (54) of the drive member
(20). A control member (41) is received in the drive member (20)
and movable relative to the switch member (42) and the drive member
(20) between a coupling position and a release position. When the
control member (41) is in the coupling position, the switch member
(42) and the control member (41) are rotatable relative to the
drive member (20) between two operative positions, and a socket can
be engaged with the other end (56) of the drive member (20). The
socket can be removed from the other end (56) of the drive member
(20) when the control member (41) is in the release position.
Inventors: |
Hu; Bobby; (Taichung,
TW) |
Correspondence
Address: |
KAMRATH & ASSOCIATES P.A.
4825 OLSON MEMORIAL HIGHWAY, SUITE 245
GOLDEN VALLEY
MN
55422
US
|
Family ID: |
41317954 |
Appl. No.: |
12/412422 |
Filed: |
March 27, 2009 |
Current U.S.
Class: |
81/62 |
Current CPC
Class: |
B25B 13/465 20130101;
B25B 23/0035 20130101 |
Class at
Publication: |
81/62 |
International
Class: |
B25B 13/46 20060101
B25B013/46 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 10, 2008 |
TW |
97121530 |
Claims
1. A ratchet wrench comprising, in combination: a head (11) and a
handle (12) interconnected to the head (11), with the head (11)
including first and second sides (18, 19) spaced in a thickness
direction, with the head (11) further including a through-hole (13)
extending from the first side (18) through the second side (19),
with the through-hole (13) including an inner periphery having a
plurality of teeth (14); a drive member (20) rotatably received in
the through-hole (13), with the drive member (20) including first
and second ends (54, 56) spaced in the thickness direction, with
the first end (54) of the drive member (20) including a first
compartment (22), with the drive member (20) further including a
hole (24) extending in the thickness direction and in communication
with the first compartment (22), with the second end (56) of the
drive member (20) including a transverse hole (26) extending in a
radial direction perpendicular to the thickness direction and
receiving a first ball (44) adapted for coupling with a socket; a
first pawl (30) pivotably received in the first compartment (22)
about a first pivot axis, with the first pawl (30) including first
and second ends (60, 62) and an inner side (64) extending between
the first and second ends (60, 62) in a longitudinal direction
perpendicular to the thickness direction, with the first end (60)
of the first pawl (30) including a plurality of first teeth (31),
with the second end (62) of the first pawl (30) including a
plurality of second teeth (36), with the inner side (64) of the
first pawl (30) including first and second positioning faces (321,
322); a switch member (42) rotatably mounted to the first end (54)
of the drive member (20), with the switch member (42) including an
engaging hole (421); a control member (41) rotatably received in
through the hole (24) of the drive member (20) between first and
second operative positions, with the control member (41) movable in
the thickness direction relative to the switch member (42) and the
drive member (20) between a coupling position and a release
position, with a first spring (43) mounted between the control
member (41) and the drive member (20) to bias the control member
(41) to the coupling position, with the control member (41)
including a first end having an engaging portion (411), with the
control member (41) further including a second end having a
recessed portion (412) spaced from the engaging portion (411) in
the thickness direction, with the recessed portion (412) receiving
the first ball (44); and a pressing device (50) mounted in the
control member (41) and including an elastic element (51) and a
first pressing member (52) biased by the elastic element (51) to
press against one of the first and second positioning faces (321,
322) of the first pawl (30) with the plurality of first teeth (31)
or the plurality of second teeth (36) engaged with the plurality of
teeth (14) of the head (11) corresponding to the first and second
operative positions of the control member (41), wherein when the
control member (41) is in the coupling position, the engaging
portion (411) of the control member (41) is engaged in the engaging
hole (421) of the switch member (42) allowing joint rotation of the
switch member (42) and the control member (41) relative to the
drive member (20) between the first and second operative positions,
and the first ball (44) is biased by the recessed portion (412) to
protrude out of the transverse hole (26) for coupling with the
socket, and wherein when the control member (41) is in the release
position, the first ball (44) is movable in the radial direction
into the recessed portion (412), allowing removal of the socket
from the second end (56) of the drive member (20).
2. The ratchet wrench as claimed in claim 1, with the switch member
(42) including inner and outer sides (427, 429) spaced in the
thickness direction, with the engaging hole (421) extending from
the inner side (427) through the outer side (429), with the switch
member (42) further including a recess (428) in the inner side
(427), forming a peripheral wall (420) having an outer diameter
larger than the through-hole (13) of the head (11), and with the
inner side (427) of the peripheral wall (420) rotatably abutting
the first side (18) of the head (11).
3. The ratchet wrench as claimed in claim 2, with the first end
(54) of the drive member (20) including an annular groove (21) in
an outer periphery thereof, with the peripheral wall (420) of the
switch member (42) further including an inner periphery having a
groove (423), with the peripheral wall (420) further including a
notch (424) having two end faces (432) and in communication with
the groove (423) of the switch member (42), with the ratchet wrench
further comprising, in combination: a retainer ring (425) received
in the groove (423) of the switch member (42) and in the annular
groove (21) of the drive member (20), with the retainer ring (425)
including two tangs (426) received in the notch (424) of the
peripheral wall (420) and abutting the two end faces (432) of the
notch (424).
4. The ratchet wrench as claimed in claim 3, with the engaging hole
(421) of the switch member (42) being non-circular in cross section
and including a plurality of surfaces (430) extending in the
thickness direction, with the engaging portion (411) of the control
member (41) being non-circular in cross section and including a
plurality of faces (418) slideably abutting the plurality of
surfaces (430) of the switch member (42) in the thickness
direction.
5. The ratchet wrench as claimed in claim 3, with the control
member (41) including a radial hole (413) extending in a radial
direction perpendicular to the thickness direction, with the
elastic element (51) and the first pressing member (52) received in
the radial hole (413).
6. The ratchet wrench as claimed in claim 5, with the first end
(54) of the drive member (20) including first and second boards
(70, 72) spaced in the thickness direction and an interconnecting
wall (74) interconnected between the first and second boards (70,
72), with the first compartment (22) defined between the first and
second boards (70, 72), with the first and second boards (70, 72)
including aligned first pivot holes (25), with the first pawl (30)
including a first pin hole (33) aligned with the two first pivot
holes (25), and with a first pin (34) extending through the first
pin hole (33) and the two first pivot holes (25) and defining the
first pivot axis.
7. The ratchet wrench as claimed in claim 6, with the first board
(70) including the annular groove (21) receiving the retainer ring
(425), with the second board (72) including a flange (27) on an
outer periphery thereof, and with the flange (27) rotatably
abutting the second side (19) of the head (11).
8. The ratchet wrench as claimed in claim 7, with the drive member
(20) further including a receptacle (90) extending in the thickness
direction through the first board (70) into the interconnecting
wall (74), with the recess (428) of the switch member (42)
including a bottom wall having first and second positioning grooves
(96, 98), with a second spring (92) and a second ball (94) being
received in the receptacle (90), with the second ball (94) biased
by the second spring (92) into one of the first and second
positioning grooves (96, 98) of the switch member (42)
corresponding to the first and second operative positions of the
control member (41).
9. The ratchet wrench as claimed in claim 8, with the first and
second boards (70, 72) including two aligned second pivot holes
(25) diametrically opposite to the two first pivot holes (25), with
the drive member (20) further including a second compartment (22)
between the first and second boards (70, 72) and in communication
with the hole (24) of the drive member (20), with the ratchet
wrench further comprising, in combination: a second pawl (30)
pivotably received in the second compartment (22) about a second
pivot axis, with the second pawl (30) including first and second
ends (60, 62) and an inner side (64) extending between the first
and second ends (60, 62) in the longitudinal direction
perpendicular to the thickness direction, with the first end (60)
of the second pawl (30) including a plurality of third teeth (31),
with the second end (62) of the second pawl (30) including a
plurality of fourth teeth (36), with the inner side (64) of the
second pawl (30) including third and fourth positioning faces (321,
322), with the second pawl (30) further including a second pin hole
(33) aligned with the two second pivot holes (25), with a second
pin (34) extending through the second pin hole (33) and the two
second pivot holes (25) and defining the second pivot axis, with
the plurality of third teeth (31) or the plurality of fourth teeth
(36) of the second pawl (30) engaged with the plurality of teeth
(14) of the head (11) corresponding to the first and second
operative positions of the control member (41).
10. The ratchet wrench as claimed in claim 9, with the radial hole
(413) being a through-hole, with the pressing device (50) further
including a second pressing member (52) received in the radial hole
(413), with the elastic element (51) mounted between the first and
second pressing members (52), and with each of the first and second
pressing members (52) being biased by the elastic element (51) to
press against one of the first and second positioning faces (321,
322) of one of the first and second pawls (30) corresponding to one
of the first and second operative positions of the control member
(41).
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a switch device and, more
particularly, to a switch device for a ratchet wrench.
[0002] Taiwan Patent Publication No. 235541 entitled "IMPROVED
RATCHET WRENCH STRUCTURE" discloses a ratchet wrench including two
pawls pivotably mounted in a pivotal rod receiving two balls. A
spring-biased push rod is extended through the pivotal rod and
includes an enlarged head on an end thereof and a recessed portion
in the other end thereof. A socket engaging ball is received in the
recessed portion. Each pawl includes an inner side having a groove
with two faces. Each ball is biased to selectively press against
one of the faces of one of the pawls. Such a ratchet wrench can
engage with a socket to drive fasteners such as bolts, nuts, etc.
in one of two operative directions while allowing free rotation in
a reverse direction. When the enlarged head of the push rod is
pressed, the socket engaging ball can be received in the recessed
portion to allow removal of the socket from the ratchet wrench.
However, the enlarged head is liable to be inadvertently pressed
when using the ratchet wrench in a small space, leading to
undesired disengagement of the socket. Furthermore, the diameter
difference between the enlarged head and the remaining portion of
the push rod is so large that a large amount of material is wasted
while manufacturing the push rod by milling. The time for
processing is long, and the costs are high. Furthermore, stress
concentration occurs in the adjoining area between the enlarged
head and the remaining portion of the push rod, such that the push
rod may break at the adjoining area.
[0003] Thus, a need exists for a ratchet wrench that has a stronger
structure and that allows reliable operation in a small space.
BRIEF SUMMARY OF THE INVENTION
[0004] The present invention solves this need and other problems in
the field of reliable operation of wrenches in a small space by
providing, in a preferred form, a ratchet wrench including a head
and a handle interconnected to the head. The head includes first
and second sides spaced in a thickness direction. The head further
includes a through-hole extending from the first side through the
second side and having an inner periphery with a plurality of
teeth. A drive member is rotatably received in the through-hole and
includes first and second ends spaced in the thickness direction.
The first end of the drive member includes a compartment. The drive
member further includes a hole extending in the thickness direction
and in communication with the compartment. The second end of the
drive member includes a transverse hole extending in a radial
direction perpendicular to the thickness direction and receiving a
ball adapted for coupling with a socket. A pawl is pivotably
received in the compartment. The pawl includes first and second
ends and an inner side extending between the first and second ends
in a longitudinal direction perpendicular to the thickness
direction. The first end of the pawl includes a plurality of first
teeth, and the second end of the pawl includes a plurality of
second teeth. The inner side of the pawl includes first and second
positioning faces. A switch member is rotatably mounted to the
first end of the drive member and includes an engaging hole. A
control member is rotatably received in the hole of the drive
member between first and second operative positions. The control
member is movable in the thickness direction relative to the switch
member and the drive member between a coupling position and a
release position. A spring is mounted between the control member
and the drive member to bias the control member to the coupling
position. The control member includes a first end having an
engaging portion. The control member further includes a second end
having a recessed portion spaced from the engaging portion in the
thickness direction. The recessed portion receives the ball. A
pressing device is mounted in the control member and includes an
elastic element and a pressing member biased by the elastic element
to press against one of the first and second positioning faces of
the pawl with the plurality of first teeth or the plurality of
second teeth engaged with the plurality of teeth of the head
corresponding to the first and second operative positions of the
control member.
[0005] When the control member is in the coupling position, the
engaging portion of the control member is engaged in the engaging
hole of the switch member allowing joint rotation of the switch
member and the control member relative to the drive member between
the first and second operative positions, and the first ball is
biased by the recessed portion to protrude out of the transverse
hole for coupling with the socket. On the other hand, when the
control member is in the release position, the ball is movable in
the radial direction into the recessed portion, allowing removal of
the socket from the second end of the drive member.
[0006] In a preferred form, the switch member includes inner and
outer sides spaced in the thickness direction. The engaging hole
extends from the inner side through the outer side. The switch
member further includes a recess in the inner side, forming a
peripheral wall having an outer diameter larger than the
through-hole of the head. The inner side of the peripheral wall
rotatably abuts the first side of the head. The peripheral wall of
the switch member further includes an inner periphery having a
groove. The peripheral wall further includes a notch in
communication with the groove of the switch member. The first end
of the drive member includes an annular groove in an outer
periphery thereof. A retainer ring is received in the groove of the
switch member and in the annular groove of the drive member. The
retainer ring includes two tangs received in the notch of the
peripheral wall and abutting two end faces of the notch.
[0007] The present invention will become clearer in light of the
following detailed description of illustrative embodiments of this
invention described in connection with the drawings.
DESCRIPTION OF THE DRAWINGS
[0008] The illustrative embodiments may best be described by
reference to the accompanying drawings where:
[0009] FIG. 1 shows a perspective view of a ratchet wrench of an
embodiment according to the preferred teachings of the present
invention.
[0010] FIG. 2 shows an exploded, perspective view of the ratchet
wrench of FIG. 1.
[0011] FIG. 3 shows a bottom, perspective view of a switch member
of the ratchet wrench of FIG. 1.
[0012] FIG. 4 shows a cross sectional view of the ratchet wrench of
FIG. 1 according to section line 4-4 of FIG. 1.
[0013] FIG. 5 shows a cross sectional view of the ratchet wrench of
FIG. 1 according to section line 5-5 of FIG. 1.
[0014] FIG. 6 is a view similar to FIG. 4 with a control member
pressed.
[0015] FIG. 7 shows an exploded, perspective view of a ratchet
wrench of another embodiment according to the preferred teachings
of the present invention.
[0016] FIG. 8 shows a cross sectional view of the ratchet wrench of
FIG. 7.
[0017] FIG. 9 shows a partial, cross sectional view of the ratchet
wrench of FIG. 1 with the control member in a first operative
position.
[0018] FIG. 10 is a view similar to FIG. 9, wherein the control
member is in a second operative position.
[0019] FIG. 11 shows a partial, cross sectional view of the ratchet
wrench of FIG. 7 with the control member in a first operative
position.
[0020] FIG. 12 is a view similar to FIG. 11, wherein the control
member is in a second operative position.
[0021] FIG. 13 shows a bottom, perspective view of a switch member
of the ratchet wrench of FIG. 7.
[0022] All figures are drawn for ease of explanation of the basic
teachings of the present invention only; the extensions of the
figures with respect to number, position, relationship, and
dimensions of the parts to form the preferred embodiment will be
explained or will be within the skill of the art after the
following teachings of the present invention have been read and
understood. Further, the exact dimensions and dimensional
proportions to conform to specific force, weight, strength, and
similar requirements will likewise be within the skill of the art
after the following teachings of the present invention have been
read and understood.
[0023] Where used in the various figures of the drawings, the same
numerals designate the same or similar parts. Furthermore, when the
terms "first", "second", "third", "fourth", "inner", "outer",
"side", "end", "portion", "section", "annular", "radial",
"longitudinal", "clockwise", "counterclockwise", "thickness", and
similar terms are used herein, it should be understood that these
terms have reference only to the structure shown in the drawings as
it would appear to a person viewing the drawings and are utilized
only to facilitate describing the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0024] A ratchet wrench according to the preferred teachings of the
present invention is shown in the drawings and generally includes a
body 10 having a head 11 and a handle 12 interconnected to head 11.
In preferred forms shown in FIGS. 1-13, head 11 includes circular
cross sections and first and second sides 18 and 19 spaced in a
thickness direction. Head 11 further includes a through-hole 13
extending from first side 18 through second side 19. Through-hole
13 includes an inner periphery having a plurality of teeth 14
extending in the thickness direction.
[0025] In the preferred forms shown in FIGS. 1-13, a drive member
20 is rotatably received in through-hole 13. Drive member 20
includes first and second ends 54 and 56 spaced in the thickness
direction. First end 54 includes first and second boards 70 and 72
spaced in the thickness direction and an interconnecting wall 74
interconnected between first and second boards 70 and 72. First
board 70 includes an annular groove 21 in an outer periphery
thereof Second board 72 includes a flange 27 on an outer periphery
thereof Flange 27 rotatably abuts second side 19 of head 11.
Furthermore, first end 54 of drive member 20 includes a hole 24
extending in the thickness direction from first end 54 to second
end 56.
[0026] In the preferred form shown in FIGS. 1-6 and 9-10, first end
54 of drive member 54 includes a compartment 22 between first and
second boards 70 and 72 and in communication with hole 24.
Furthermore, first and second boards 70 and 72 include two aligned
first pivot holes 25 in communication with compartment 22. In the
preferred form shown in FIGS. 7-8 and 11-13, first end 54 of drive
member 54 includes two compartments 22 between first and second
boards 70 and 72 and in communication with each other via hole 24.
Furthermore, first and second boards 70 and 72 includes two aligned
second pivot holes 25 diametrically opposite to first pivot holes
25 and in communication with second compartment 22. Further, first
end 54 includes a receptacle 90 extending in the thickness
direction from first board 70 into interconnecting wall 74 and
receiving a spring 92 and a ball 94.
[0027] In the preferred forms shown in FIGS. 1-13, hole 24 includes
a first stepped portion 85 in first board 70 and a stepped portion
86 in second board 72, dividing hole 24 into first, second, and
third sections 242, 244, and 246 from first end 54 to second end 56
of drive member 20, with first section 242 having a diameter larger
than that of second section 244, which in turn, is larger than that
of third section 246. Furthermore, second end 56 of drive member 20
is in the form of a drive column 23 located outside of head 11 and
having square cross sections. Second end 56 of drive member 20
includes a transverse hole 26 receiving a ball 44 and in
communication with third section 246 of hole 24. Drive column 23
can be releasably coupled with a socket for driving a fastener.
Other forms of second end 56 of drive member 20 for directly or
indirectly engaging with a fastener to be loosened or tightened
would be within the skill of the art.
[0028] In the preferred form shown in FIGS. 1-6 and 9-10, a pawl 30
is pivotably received in compartment 22. Pawl 30 includes first and
second ends 60 and 62 and an inner side 64 extending between first
and second sides 60 and 62 in a longitudinal direction
perpendicular to the thickness direction. First end 60 of pawl 30
includes a plurality of first teeth 31, and second end 62 of pawl
30 includes a plurality of second teeth 32. Inner side 64 of pawl
30 includes a positioning section 32 in the preferred form shown as
an arcuate groove having first and second positioning faces 321 and
322 spaced in the longitudinal direction. Pawl 30 further includes
upper and lower faces 66 and 68 spaced in the thickness direction
and a pin hole 33 extending from upper face 66 through lower face
68. A pin 34 is extended through pivot holes 25 of drive member 20
and pin hole 33 of pawl 30 and defines a pivot axis about which
pawl 30 is pivotable. In the preferred form shown in FIGS. 7-8 and
11-13, first and second pawls 30 are received in compartment 22 and
each have a structure substantially the same as that of pawl 30 of
FIGS. 1-6 and 9-10. Furthermore, in addition to first pin 34
extending through first pivot holes 25 of drive member 20 and pin
hole 33 of first pawl 30, a second pin 34 is extended through
second pivot holes 25 of drive member 20 and pin hole 33 of second
pawl 30 and defines a second pivot axis about which second pawl 30
is pivotable.
[0029] In the preferred forms shown in FIGS. 1-13, the ratchet
wrench further includes a switching device 40 including a control
member 41 and a switch member 42. Control member 41 includes a
larger section 414 and a smaller section 416 having a diameter
smaller than larger section 414. A non-circular engaging portion
411 is formed on an end of larger section 414 distant to smaller
section 416. Engaging portion 411 has a diameter larger than larger
section 414 and is hexagonal in cross section and has six faces 418
extending in the thickness direction in the preferred forms shown
in FIGS. 1-13. Larger section 414 includes a radial hole 413
extending in a radial direction perpendicular to the thickness
direction. In the preferred form shown in FIGS. 1-6 and 9-10,
radial hole 413 is a blind hole. In the preferred form shown in
FIGS. 7-8 and 11-13, radial hole 413 is a through-hole.
[0030] In the preferred forms shown in FIGS. 1-13, a recessed
portion 412 in the form of a stepped groove is formed on an end of
smaller section 416 distant to larger section 414 and spaced from
engaging portion 411 in the thickness direction and includes a
deeper section and a shallower section. A ball 44 is received in
transverse hole 26 of drive member 20 and recessed portion 412 of
control member 41. Ball 44 is normally biased by a bottom wall of
the shallower section of recessed portion 412 to a position
partially beyond transverse hole 26 for coupling with a socket.
[0031] In the preferred forms shown in FIGS. 1-13, switch member 42
includes inner and outer sides 427 and 429 spaced in the thickness
direction and a non-circular engaging hole 421 extending from a
center of inner side 427 through a center of outer side 429.
Engaging hole 421 includes a plurality of surfaces 430 extending in
the thickness direction and is hexagonal in cross section in the
preferred forms shown in FIGS. 1-13. Switch member 42 further
includes a recess 428 in inner side 427, forming a peripheral wall
420 having an outer diameter larger than through-hole 13 of head
11. An anti-slipping section 422 is formed on an outer periphery of
peripheral wall 420. Furthermore, a groove 423 is defined in an
inner periphery of peripheral wall 420. Peripheral wall 420 further
includes a notch 424 in communication with groove 423 and defined
by two end faces 432. In the preferred form shown in FIGS. 1-13,
switch member 42 further includes first and second positioning
groove 96 and 98 formed in a bottom wall of recess 428.
[0032] In the preferred forms shown in FIGS. 1-13, a retainer ring
425 is received in groove 423 of switch member 42 and in annular
groove 21 of drive member 20 and includes two tangs 426 received in
notch 424 and abutting end faces 432. Thus, switch member 42 is
rotatably mounted around first end 54 of drive member 20. Inner
side 427 of peripheral wall 420 of switch member 42 rotatably abuts
first side 18 of head 11, and flange 27 of drive member 20
rotatably abuts second side 19 of head 11, preventing disengagement
of drive member 20 from head 11. Engaging portion 411 of control
member 41 is normally engaged in engaging hole 421 of switch member
42 with faces 418 of engaging portion 411 slideably abutting
surfaces 430 of engaging hole 421, allowing joint rotation of
control member 41 and switch member 42 relative to drive member 20
while allowing movement of control member 41 relative to switch
member 42 and drive member 20 in the thickness direction.
[0033] In the preferred forms shown in FIGS. 1-13, control member
41 is pivotably extended through hole 24 of drive member 20, with
smaller section 416 received in third section 246 of hole 24, and
with larger section 414 received in second section 244 of hole 24.
A spring 43 is mounted between an end face of larger section 414
and second stepped portion 86 of hole 24. Spring 43 biases control
member 41 to a coupling position such that ball 44 is partially
pushed out of hole 26 by the bottom wall of the shallower section
of recessed portion 412 (FIG. 4), allowing secure coupling between
drive column 23 and a socket. Note that engaging portion 411 of
control member 41 is engaged in engaging hole 421 of switch member
42 when control member 41 is in the coupling position.
[0034] In the preferred forms shown in FIGS. 1-13, the ratchet
wrench further includes a pressing device 50 for retaining pawl 30
in place. Pressing device 50 is mounted in radial hole 413 of
control member 41. In the preferred form shown in FIGS. 1-6 and
9-10, pressing device 50 includes a pressing member 52 in the form
shown as a ball and an elastic element 51 in the form shown as a
spring. Elastic element 51 biases pressing member 52 to partially
protrude out of radial hole 413 to press against positioning
section 32 of pawl 30. In the preferred form shown in FIGS. 7-8 and
11-13, pressing device 50 includes first and second pressing
members 52 in the form shown as two balls and an elastic element 51
in the form shown as a spring. Elastic element 51 biases first and
second pressing members 52 to partially protrude out of radial hole
413 to press against pressing sections 32 of first and second pawls
30.
[0035] Now that the basic construction of the ratchet wrench of the
preferred teachings of the present invention has been explained,
the operation and some of the advantages of the ratchet wrench can
be set forth and appreciated. In the preferred form shown in FIGS.
1-13, control member 41 can be pivoted relative to drive member 20
between first and second operative positions by manually rotating
switch member 41.
[0036] In the preferred form shown in FIGS. 1-6 and 9-10, when
control member 41 is in the first operative position (FIG. 9), ball
94 is biased by spring 92 into first positioning groove 96 of
switch member 42, and pressing member 52 presses against first
positioning face 321 of pawl 30 under the action of elastic element
51. First teeth 31 of pawl 30 are disengaged from teeth 14 of head
11, and second teeth 36 of pawl 30 are engaged with teeth 14 of
head 11. In this state, handle 12 and drive member 20 can rotate in
the counterclockwise direction to drive a fastener in the
counterclockwise direction. Furthermore, handle 12 can rotate
freely relative to drive member 20 in the clockwise direction
without driving the fastener. When the control member 41 is in the
second operative position (FIG. 10), ball 94 is biased by spring 92
into second positioning groove 98 of switch member 42, and pressing
member 52 presses against second positioning face 322 of pawl 30.
First teeth 31 of pawl 30 are engaged with teeth 14 of head 11.
Furthermore, second teeth 36 of pawl 30 are disengaged from teeth
14 of head 11. In this state, handle 12 and drive member 20 can
rotate in the clockwise direction to drive the fastener in the
clockwise direction. Furthermore, handle 12 can rotate freely
relative to drive member 20 in the counterclockwise direction
without driving the fastener.
[0037] In the preferred form shown in FIGS. 7-8 and 11-13, when
control member 41 is in the first operative position (FIG. 11),
ball 94 is biased by spring 92 into first positioning groove 96 of
switch member 42. First pressing member 52 presses against first
positioning face 321 of first pawl 30, and second pressing member
52 presses against second pressing face 322 of second pawl 30.
First teeth 31 of first pawl 30 and second teeth 36 of second pawl
30 are disengaged from teeth 14 of head 11. Furthermore, second
teeth 36 of first pawl 30 and first teeth 31 of second pawl 30 are
engaged with teeth 14 of head 11. In this state, handle 12 and
drive member 20 can rotate in the counterclockwise direction to
drive the fastener in the counterclockwise direction. Furthermore,
handle 12 can rotate freely relative to drive member 20 in the
clockwise direction without driving the fastener. When control
member 40 is in the second operative position (FIG. 12), ball 94 is
biased by spring 92 into second positioning groove 98 of switch
member 42. First pressing member 52 presses against second
positioning face 322 of first pawl 30, and second pressing member
52 presses against first pressing face 321 of second pawl 30. First
teeth 31 of first pawl 30 and second teeth 36 of second pawl 30 are
engaged with teeth 14 of head 11. Furthermore, second teeth 36 of
first pawl 30 and first teeth 31 of second pawl 30 are disengaged
from teeth 14 of head 11. In this state, handle 12 and drive member
20 can rotate in the clockwise direction to drive the fastener in
the clockwise direction. Furthermore, handle 12 can rotate freely
relative to drive member 20 in the counterclockwise direction
without driving the fastener.
[0038] In the preferred forms shown in FIGS. 1-13, when control
member 41 is pressed in the thickness direction towards drive
column 23 to a release position, spring 43 is compressed, and ball
44 can be received in the deeper section of recessed portion 412
(FIG. 6), allowing disengagement of the socket from drive column
23. It can be appreciated that switch member 42 does not move while
control member 41 is moving in the thickness direction. When using
the ratchet wrench in a small space, switch member 42 does not move
in the thickness direction even if it is inadvertently impinged.
Thus, undesired disengagement of the socket from the drive column
23 is avoided. Furthermore, switch member 42 and control member 41
can be easily manufactured separately, reducing the manufacturing
costs while providing stronger structural strength and avoiding
stress concentration problems encountered in conventional ratchet
wrenches with a push rod.
[0039] Now that the basic teachings of the present invention have
been explained, many extensions and variations will be obvious to
one having ordinary skill in the art. For example, although the
ratchet wrenches shown in the preferred forms include only two
operative positions, the structures of pawls 30 can be modified to
provide a third operative position intermediate the first and
second operative positions. As an example, when the ratchet wrench
of FIGS. 7-8 and 11-13 in the third operative position, first teeth
31 of first and second pawls 30 are engaged with teeth 14 of head
11 while second teeth 36 of first and second pawls 30 are
disengaged from teeth 14 of head 11, allowing handle 12 and drive
member 20 to rotate jointly in the same direction and preventing
handle 12 to rotate in a reverse direction relative to drive member
20. This allows a user to proceed with slight adjustment of
tightness of the fastener.
[0040] Thus since the invention disclosed herein may be embodied in
other specific forms without departing from the spirit or general
characteristics thereof, some of which forms have been indicated,
the embodiments described herein are to be considered in all
respects illustrative and not restrictive. The scope of the
invention is to be indicated by the appended claims, rather than by
the foregoing description, and all changes which come within the
meaning and range of equivalency of the claims are intended to be
embraced therein.
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